The present application relates generally to featherseals and more specifically to a system and method for preparing a featherseal slot with a lightening pocket on a workpiece.
Gas turbine engines are utilized at high temperatures in order to maximize their efficiency. In order to operate at such temperatures, cooling is provided to select components, such as turbine vanes, thereby preventing overheating. In order for a coolant to reach the select components cooling paths, which have a curved shape, are used. Due to the cooling path shape, the turbine vanes are typically constructed out of segmented components to allow for maintaining the integrity of the cooling path despite differential expansion.
Coolant escapes between the segments of the segmented cooling path. Thus, a seal is placed between each of the segmented components and its adjacent components to create a single sealed pathway. The seal is a sheet of material, such as a metal, which is placed partially within a slot in one of the segments, and partially within a slot in the adjacent segment, thereby sealing the joint between the slots. Such a sealing arrangement is referred to as a featherseal.
When the engine is operating, pressure from the coolant holds the seal in place against the slot's wall on the low pressure side. Additionally, when the engine is not operational only a partial wall for the feather seal slot on the high pressure side is necessary to hold the featherseal in place. Since a full featherseal slot is not required at any time, a portion of the segment on the high pressure side can be removed creating a pocket with less material, thereby lightening the component. In order to create the lightening pocket, current state of the art techniques involve casting the part with the pocket removed.